EWP: GOES optical depth retrieval enhances UW-CTC

The inability for the UW-CTC algorithm to detect newly developing convection beneath thin cirrus clouds was the primary deficiency identified by forecasters in previous experiments.  In response to forecaster feedback, a recent proposal was awarded to UW/CIMSS to include GOES optical depth retrievals into the UW-CTC algorithm for the purpose of detecting these type of developing thunderstorms.  Thin cirrus clouds are frequently present related to anvil blow off of nearby storms, decayed convection from previous days, and related to jet streaks.  Figure 1 below provides another example of detecting a newly developing convective cloud in areas of thin cirrus.  The UW-CTC value is ~ -9K /15 min and the tower beneath the thin cirrus clouds can be seen in the upper right panel highlighted by the red circle.  Since this storm was out of our focus domain, radar data is not available, but NLDN detected the first lightning strike about 10 minutes later.

Figure 1.  Valid 2115 UTC 09 May 2012.  Note the developing thunderstorm beneath cirrus blow-off from storms to the south (red circle, top left panel).  The corresponding UW-CTC was ~ -9 K /15 min.  The bottom right panel shows the UW-CTC ice mask, which shows areas where detection was not possible prior to the inclusion of GOES optical depth retrievals.